A pair of suicide bombers killed 12 people in attacks on pro-government tribal members in southern Yemen today.

The first suicide bomber detonated his vest in a crowd of people after greeting them in the town of Mudiyah in the southern province of Abyan, Reuters reported. Mudiyah is 30 northeast of Shaqra, which fell under the control of al Qaeda in the Arabian Peninsua last week, and 50 miles northeast of Zinjibar, the provincial capital of Abyan which fell under AQAP control in late May.

AQAP has been battling pro-government tribes and the military in Mudiyah. Tribesmen claimed they killed Yassir al-Shalily, a leader of the Ansar al Shariah, during fighting in Mudiyah on Aug. 10. Ansar al Shariah is the political front group for al Qaeda in the Arabian Peninsula and allied Yemeni terrorist groups.

The second suicide attack today took place at a checkpoint manned by tribal fighters in the Al Arqub area near Mudiyah. Nine tribal fighters were killed in the blast, Reuters reported.

Background on AQAP and Ansar al Sharia

Al Qaeda in the Arabian Peninsula has been fighting under the banner of the Ansar al Sharia, or the Army of Islamic law. Ansar al Sharia constitutes “AQAP’s version of the Islamic State of Iraq,” which is al Qaeda’s political and military front in Iraq, a senior US intelligence official told The Long War Journal. “Ansar al Sharia is pulling in allied Islamist groups and sympathetic tribes into its orbit, and seeks to implement an Islamic State much like the Taliban did in Afghanistan and al Qaeda attempted in Iraq,” he said.

In an official statement released by Ansar al Sharia in May 2011, the group said it wishes to take control of “all administrative, political, economic, cultural, monitoring, and other responsibilities” in Yemen.

AQAP is seeking to build an army to back up its Islamic state. Last summer, Qasim al Raymi, the military commander for al Qaeda in the Arabian Peninsula, and Mohammed Said al Umdah Gharib al T’aizzi, a senior AQAP military commander in southern Yemen, both claimed that the terror group had raised a 12,000-fighter-strong army in the southern Yemeni provinces. Yemeni officials recently told Al Hayah that “al Qaeda fighters in Zinjibar (the capital of Abyan) number in the hundreds, and perhaps exceed 2,000 gunmen.”

For the past several months, Yemeni security forces have been battling AQAP and allied Islamist groups for control of the south. AQAP is known to have openly taken control of areas in Abyan, Shabwah, Hadramawt, Marib, and Lahj since the onset of large anti-government protests in March. Government forces have withdrawn from major cities in the south, leaving an opening for al Qaeda and allied Islamist groups to seize control of several areas. In May, AQAP took over Zinjibar, the provincial capital of Abyan. In June, AQAP seized Azzan, a city in Shabwah province. Last week, AQAP seized the coastal city Shaqra in Abyan province. Now Yemenis describe the southern port city of Aden as ripe for an AQAP takeover.

Yemen has become one of al Qaeda’s most secure bases and a hub for its activities on the Arabian Peninsula and on the Horn of Africa. AQAP maintains safe havens in various parts of the country and is also known to operate terror camps in Aden, Marib, and Abyan, and in the Alehimp and Sanhan regions in Sana’a. The terror group has conducted attacks on oil facilities, tourists, the US embassy in Sana’a, and Yemeni security forces.

AQAP’s base in Yemen serves as a command and control center, a logistics hub, a transit point from Asia and the Peninsula, and a source of weapons and munitions for the al Qaeda-backed Shabaab in Somalia.

AQAP has also used its Yemeni base as a hub for attacks against the West. The 2009 Fort Hood shootings and the Christmas Day airline plot, as well as an airline parcel bomb plot in 2010, have all been traced back to Yemen.

“Yemen is Pakistan in the heart of the Arab world,” a US intelligence official told The Long War Journal in 2009. “You have military and government collusion with al Qaeda, peace agreements, budding terror camps, and the export of jihad to neighboring countries.”

The US is said to be taking advantage of the security vacuum in Yemen to step up attacks against AQAP’s top leaders and its network. The US has launched at least four airstrikes in Yemen since May. Yemen has become enmeshed in a civil war that pits government factions, a rival military commander, the political opposition, various tribes, Shia Houthi rebels, and AQAP all against each other. Over the past several months, the fighting has intensified. President Ali Saleh has left the country for medical treatment after suffering a brain injury as well as burns on 40 percent of his body following an explosion at a mosque in the presidential compound in June.